Heat actuated snap acting valve



Dec. 18, 1962 J. c. HEWITT, JR

HEAT ACTUATED SNAP ACTING VALVE Filed Jan. 20, 1958 United States Patent()fifice 3,069,125 Patented Dec. 18, 1962 3,069,125 HEAT ACTUATED SNAPACTING VALVE John C. Hewitt, Jr., Long Beach, Calif., assignor toRobertshaw-Fulton Controls Company, Richmond, Va., a corporation ofDelaware Filed Jan. 20, 1958, Ser. No. 703,851 8 Claims. (Cl. 251-11)This invention relates to valves and more particularly to a heatactuated snap acting valve.

An object of this invention is to utilize a snap acting device as avalve member.

Another object of this invention is to actuate a snap acting valvemember in response to temperature vari ations.

A further object of this invention is to support a heat responsive valvemember on a hollow member which houses electric heating means.

It is a further object of this invention to control the flow of fluidthrough a valve casing by a heat responsive valve member and apply heatto the valve member by means of electric heating means sealed from theflow of fluid.

In carrying out this invention, a casing is provided with an inlet andan outlet passage intersected by a valve seat. A snap acting disc valvemember is positioned to have a portion thereof movable relative to thevalve seat in response to temperature variations. A tubular memberprovides support for the valve member and houses an electric heatingelement which is operative to vary the temperature condition.

Other objects and advantages will become apparent from the followingdescription taken in connection with the accompanying drawings, wherein:

FIG. 1 is a longitudinal sectional view of a valve embodying thisinvention; and

FIG. 2 is a fragmentary sectional view of a valve showing a modificationof this invention.

Referring more particularly to FIG. 1, the valve comprises a casinghaving an inlet passage 12 in one end and an outlet passage 14 in theother end. The casing 10 is provided with a valve chamber 16intermediately disposed between the inlet and outlet passages 12 and 14which are intersected by an annular valve seat 18 formed in the chamber16 on an internal wall of casing 10. A cover plate 20 seals the upperend of chamber 16 and is secured to casing 10 with a gasket therebetweenby any suitable fastening means such as screws 22.

A hollow tubular support member, indicated generally at 24, ispositioned in axial alignment with the valve seat 18 and has a lowerthreaded portion 26 extending through the bottom wall of casing 10. Asuitable nut 28 is threaded on portion 26 and tightened to draw ashoulder 30 on a support member 24 into engagement with the internalbottom wall of casing 10 to secure the support member 24. The other endof the tubular support 24 terminates centrally of the valve seat 18 andflanges radially outwardly and upwardly to form a boss 32 which ha anupper convex end face 34 spaced upwardly of the plane of the annularvalve seat 18.

A genera-11y dish-shaped snap acting disc 36 is utilized as a valvemember and supported on the end face 34 in axial alignment with thetubular support 24 and valve seat 18 to control a fluidflow between theinlet passage 12 and the outlet passage 14. An annular member or ring 37of any suitable sealing material is fixed to the peripheral portion ofdisc 36 on the underside thereof and is operative to engage the valveseat 18 in the position of the disc 36 shown in FIG. 1. The disc 36 isprovided with a generally conical indentation 38 in the central portionthereof, which engages a complemental depression 40 in the end face 34to maintain axial alignment of the disc 36 with the valve seat 18.

, A rod-like element 42 has one end secured to the central portion ofcover 20 and another end extending toward the disc 36 in axial alignmentwith the hollow support 24. The lower end of rod 42 is rounded and abutsthe bottom wall of the indentation 38 to hold the disc 36 firmly inengagement with the end face 34. The rod 42 and hollow member 24 thuscooperate to support and fix the central portion of the disc 36relativeto the casing 10.

As indicated on the drawing, the disc 36 is constructed of a suitablebimetal material so as to deform with a snap action in response totemperature variations in a manner which is well known in the art. Whenthe disc 36 is cold, it will have an inherent bias towards thedishshaped configuration shown in solid lines in FIG. 1 and the, ring 37will engage the valve seat 18 to prevent a fluid flow through chamber 16from the inlet passage 12 to the outlet passage 14. In response to anincrease of heat, the disc 36 will deform to move the ring 37 out ofengagement with the valve seat 18. Since the position of the medialportion of disc 36 is fixed by the support member 24 and rod 42,application of heat to the disc 36 will cause the periphery thereof tomove relative to its medial portion upwardly to the position illustratedin dashed lines at 44. As the periphery of the disc 36 moves upward inthis manner, it will move through a dead center position relative to themedial portion whereupon such peripheral portion will move with snapac-'- tion to its dashed-line position 44 permitting a fluid flow frominlet passage 12 to outlet passage 14. I 1 The tubular support 24 isprovided with an internal bore 46 which houses electric heating means.The electric heating means includes a hollow stem 48 having an upper endengaging a conical recess at the end of bore 46 and a lower end fixedwithin an insulating sleeve 50 which seals the lower end of bore 46. Aheating coil 52 is spirally wound on the upper end of stem 48 and iselectrically connected to suitable lead wires 54 and 56 which extendfrom the interior of stem 48 to the exterior of casing 10. When theheating coil 52 is ener gized, heat will be transferred therefrom to thetubular support 24 and in turn conducted to the disc 36 to heat thesame.

While not limited to, this invention is particularly adapted to thecontrol of a fluid fuel burner such as is employed in a house heatingsystem. To this end, the lead wire 56 is connected to line wire L1 of asuitable power source and a lead wire 54 is connected to another linewire L2 of the source. A thermostat 58 is shown schematically as havinga switch arm 60 cooperable with a fixed contact 62 and may be connectedin the lead wire 54 to control energization of the heating coil 52. Inoperation, the switch arm 60 is moved into engagement with the fixedcontact 62 in response to a demand for heat. The subsequent energizationof coil 52 effects movement of the snap disc 36 to its dashed-lineposition 44 whereby fuel from a source (not shown) flows from inletpassage 12 through chamber 16 to outlet passage 14 for delivery to afluid fuel burner (not shown).

If the temperature of the room or space within which the thermostat 58is positioned corresponds to or exceeds the control temperature of thethermostat 58, the switch arm 60 will be out of engagement with thefixed contact 62 and the heating coil 52 will be de-energized. In thiscondition of the apparatus, the bimetal disc 36 will be cold and assumethe position shown in solid lines wherein the ring 37 engages the seat18 to prevent the fluid flow. When the temperature of the space aroundthe thermostat 58 drops below the control temperature thereof, theswitch arm 60 will move into engagement with the fixed contact 62 toenergize the heating coil 52. The heat from heating coil 52 istransferred by conduction through the wall of the tubular support 24 andboss 32 to the snap acting disc 36 causing movement thereof to thedashed-line position 44 to permit the flow of the fluid.

In the modification illustrated in FIG. 2, the same reference numeralsof the modification in FIG. 1 have been utilized for identical elementsand reference numerals with 100 added have been utilized for similarelements. Consequently, the following description excludes thoseidentical elements which have been described previously.

A hollow tubular support member, indicated generally at 124, is formedof a thermally responsive material so as to be expansible andcontractible in response to the heating condition of electric coil 52.The upper end of the tubular support 124 terminates centrally of thevalve seat 18 and flanges perpendicularly outwardly to form a plate 132which is provided with an annular rim 134 extending upwardly from theplane of the annular valve seat 18.

A generally dish-shaped snap acting disc and valve member 136 differsfrom the disc 36 in FIG. 1 by being constructed of a single metal toform a clicker disc which is well known in the art. The clicker disc 136is supported on the annular rim 134 of the tubular support 124 in axialalignment therewith. An annular ring 137 of any suitable sealingmaterial is fixed to the peripheral portion of disc 136 on the undersidethereof and is operative to engage the valve seat 18 in the positionshown in FIG. 2. The clicker disc 136 is provided with a generallyconical indentation 138 in the central portion thereof which hasabutting engagement with the lower end of rod 42.

During operation of the device shown in FIG. 2, the heating coil 52 isenergized causing the thermally responsive tubular support 124 to expandin an upward direction. The upward movement of tubular support 124 andits annular rim 134 presses the clicker disc 136 against the fulcrum rod42 causing the peripheral portion thereof to move relative to its medialportion upwardly to the position illustrated in dashed lines at 144. Asthe peripheral portion of the disc 136 moves upward in this manner, itwill move through a dead center position relative to its medial portionwhereupon such peripheral portion will move with a snap action to itsdashed line position 144 where it is separated from the valve seat 18and a flow of fluid is permitted. When the clicker disc 144 assumes itsdashed line position 144, the medial portion thereof will be moved outof engagement with rod 42 and into engagement with the upper surface ofcircular plate 132.

Inasmuch as various changes may be made in the details and theconstruction herein disclosed, it is intended that the foregoingdescriptions and drawings be interpreted as illustrative and not in alimiting sense.

I claim:

1. In a valve, the combination comprising a casing having a pair ofpassages separated by a valve seat, a thermally responsive valve membermovable relative to the valve seat for controlling a fluid flow betweenthe passages in response to temperature variations, a hollow memberpositioned in said casing and supporting the medial portion of saidvalve member, and electric heating means disposed in said hollow memberand being operative when energized to heat said medial portion supportedby said hollow member to effect actuation of said thermally responsivevalve member.

2. In a valve for controlling a fluid flow, the combination comprising acasing having inlet and outlet passages separated by a valve seat, abimetal valve member having a portion thereof cooperating with the valveseat for controlling the fluid flow in response to temperaturevariations, a hollow member extending from a wall of said casing andproviding support for the medial portion of said valve member, andelectric heating means positioned in said hollow member and beingoperative when energized to heat said medial portion of said bimetalvalve member by conduction through said hollow member to effect movementof the valve member portion relative to the valve seat.

3. In a valve, the combination comprising a casing having inlet andoutlet passages intersected by a valve seat, a bimetal valve member ofgenerally dish-shaped configuration having a peripheral portion movablewith a snap action relative to a medial portion thereof upon applicationof heat to said valve member, means for supporting said medial portionin said casing to effect snap movement of said peripheral portion intoand out of engagement with the valve seat for controlling a fluid flowbetween said passages, and electric heating means disposed in proximityto said supporting means of said bimetal valve member for heating thesupporting means to actuate said bimetal valve member.

4. In a valve, the combination comprising a casing having inlet andoutlet passages intersected by a valve seat, a generally dish-shapedvalve member having a peripheral portion movable with a snap actionrelative to a medial portion, an expansible and contractible hollowmember extending from a wall of said casing in axial alignment with thevalve seat and having an end engaging the medial portion wherebyexpansion and contraction of said hollow member effects movement of theperipheral portion relative to the valve seat for controlling a fluidflow between said passages, and means extending from an opposite wall ofsaid casing and abutting the medial portion of said valve member forholding the same in engagement with the end of said hollow member.

5. The combination as recited in claim 4 wherein electric heating meansis disposed in said hollow member and is operative when energized toeffect expansion of said hollow member.

6. In a valve for controlling a fluid flow, the combination comprising acasing having a pair of passages separated by a valve seat, asnap-acting disc cooperating with the valve seat for controlling thefluid flow between the passages, and thermal means positioned in saidcasing and thermally conductively engaging said disc to cause snapactionthereof in response to temperature variations, said thermal meansincluding a hollow member extending from a wall of said casing insupporting relation with said disc.

7. In a valve for controlling a fluid flow, the combination comprising acasing having a pair of passages separated by a valve seat, atemperature responsive valve member assembly comprising a valve memberhaving a peripheral portion thereof cooperating with the valve seat forcontrolling the fluid flow and a hollow member extending from a wall ofsaid casing and providing a support for the medial portion of said valvemember, and electric heating means positioned within said hollow memberand being operative when energized to heat said medial portion of saidvalve member assembly to effect movement of said peripheral portion ofsaid valve member portion relative to the valve seat.

8. In a valve for controlling a fluid flow, the combination comprising acasing having an inlet and outlet passage intersected by a valve seat, abimetal valve mem- 5 ber of generally dish-shaped configurationpositioned in axial alignment With the valve seat and having aperipheral portion movable With a snap action relative to a medialportion upon application of heat to said valve member, a tubular memberextending from one wall of said casing in axial alignment with saidvalve member and having an end engaging the medial portion of said valvemember, an electric heating element positioned within said tubularmember and operative when energized to heat said valve member byconduction through said tubular member to eifect movement of said valvemember relative to the valve seat, and an abutting member extending froman opposite wall of said casing for holding said valve member intoengagement with said tubular member.

References Cited in the file of this patent UNITED STATES PATENTS2,301,318 Peo Nov. 10, 1942 2,484,405 Eskin Oct. 11, 1949 2,515,229Jenkins July 18, 1950 2,698,022 Fahnoe Dec. 28, 1954 10 2,833,507 DubeMay 6, 1958 FOREIGN PATENTS 437,391 Great Britain l935

